New to MIG with Shielding Gas Question

admin

For the last 10 years I have used 0.035 flux cored wire with my Lincoln SP-100. Decided to try 0.030 with 75/25 AR/CO shielding gas. I switched my polarity to DC+ and proceeded to do some practice stringer beads using 25cuft/hr.2 things that I noticed:1) When I weld with flux core, I can run a continous bead with a pretty much consistant sound. With my first gas shielding tries it sounds like the power is going up and down...almost like there is a voltage drop...then it comes back every 3 seconds or so. Did this with various wire speeds and voltage settings.2) The chart inside the cover of my welder gives guidelines for volatge and wire speeds. Sure seems like I have to go al ot lower than the reccomended settings. I was trying some flat 16ga steel and burnt through it almost immediately. Once I set it to what was reccomended for 20 ga, it seemed almost perfect.Any comments on what I described?Bruce"Common sense is not very common"http://www.tahoekeyshome.com
Reply:can you post pictures?
Reply:Some things that come to mind are: you might back off on your gas you should be able to run it some place between 15-20. Did you blow out your liner before loading the solid wire in it? You might make sure your gas orifices are clean inside your torch head. Also don't know what kind of a roller you have in your welder but I have had trouble after making the switch from flux to solid before and found that the roller was knurled when setting it at the same pressure I had been running the flux core wire at I noticed that I was getting little indentions on my wire that were causing problems as it got to the contact tip. Backing off on the pressure or going to a smooth roller might help on this or making sure that the roller does not have a bunch of build up on it from running the flux wire.     Finally the settings on the machine are always just a ballpark area for starting with as you probably know, sometimes you have to tweak the settings to get to the sweat spot for welding. I really think once everything is going right for you that you will be very happy you made the switch. I very seldom ever run flux core anymore unless I have ran out of solid wire or gas and I am right in the middle of a project or I have to weld something out doors. That brings up another question, you do not have a fan or other type of airflow coming accross that would be messing with you running the solid wire and gas would you?
Reply:gnewby,Thanks for the suggestions. I will try these and get back.As far as the look of the welds go, they look pretty good. They seem a bit thick like there isn't enough heat but since if I boost up the voltage and I burn through, I think I am close to being correct.The noise it makes is almost like a vrrrrrip...pop...vrrrip..pop  and so on "Common sense is not very common"http://www.tahoekeyshome.com
Reply:One more thing mig welding really likes clean shinny metal, you might be sure yours is that way.
Reply:I am new here, but been welding for a long time.  It sounds like you are haveing feeding problems.  If you can remove the liner, spray some cleaner through it then blow air , it should cean it out.Quote  As far as the look of the welds go, they look pretty good. They seem a bit thick like there isn't enough heat but since if I boost up the voltage and I burn through, I think I am close to being correct.  QuoteThe wire speed is the heat.   Pick that first and fine tune the voltage so you get a smooth buzzzzz when welding.  If you have taps, you have to fine tune the wire speed.I have about 2 or 3 partial rolls of cored wire, never use em.  Bare wire is the only way to fly at least for me.Also try to weld the two pieces together pausing at each side (weave) instead of welding the joint.  You should end up with a flatter nicer looking bead.David
Reply:Ok...found 95%of my problem was the wire feed. The wire feed was jerky. Cleaned the liner and moved the roller around to the finer groove. I figured I should have been in the wider groove but maybe it is worn from the years of doing 0.035.Now I need to work on wire feed voltage combos to get good beads."Common sense is not very common"http://www.tahoekeyshome.com